Synthetic radioisotope

Source: Wikipedia, the free encyclopedia.

A synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. Examples include technetium-99 and promethium-146. Many of these are found in, and harvested from, spent nuclear fuel assemblies. Some must be manufactured in particle accelerators.[1]

Production

Some synthetic radioisotopes are extracted from spent

fission products. For example, it is estimated that up to 1994, about 49,000 terabecquerels (78 metric tons) of technetium were produced in nuclear reactors; as such, anthropogenic technetium is far more abundant than technetium from natural radioactivity.[2]

Some synthetic isotopes are produced in significant quantities by fission but are not yet being reclaimed. Other isotopes are manufactured by

ruthenium-96) or by bombarding parent isotopes with high energy particles from a particle accelerator.[3][4]

Many isotopes, including

oxygen-15 are widely used in positron emission tomography.[5]

Uses

Most synthetic radioisotopes have a short half-life. Though a health hazard, radioactive materials have many medical and industrial uses.

Nuclear medicine

The field of nuclear medicine covers use of radioisotopes for diagnosis or treatment.

Diagnosis

Radioactive tracer compounds, radiopharmaceuticals, are used to observe the function of various organs and body systems. These compounds use a chemical tracer which is attracted to or concentrated by the activity which is being studied. That chemical tracer incorporates a short lived radioactive isotope, usually one which emits a gamma ray which is energetic enough to travel through the body and be captured outside by a gamma camera to map the concentrations. Gamma cameras and other similar detectors are highly efficient, and the tracer compounds are generally very effective at concentrating at the areas of interest, so the total amounts of radioactive material needed are very small.

The metastable

molybdenum-99 was 440 TBq (12,000 Ci) in 2010, overwhelmingly provided by fission of uranium-235.[6]

Treatment

Several radioisotopes and compounds are used for

medical treatment, usually by bringing the radioactive isotope to a high concentration in the body near a particular organ. For example, iodine-131 is used for treating some disorders and tumors of the thyroid
gland.

Industrial radiation sources

process control, food irradiation and underground detection.[7][8][9]

Footnotes

  1. ^ "Radioisotopes". www.iaea.org. 2016-07-15. Retrieved 2023-06-25.
  2. ISBN 978-3-540-59469-7
    .
  3. ^ "Radioisotope Production". Brookhaven National Laboratory. 2009. Archived from the original on 6 January 2010.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  4. ISBN 92-0-101103-2
    .
  5. ISBN 978-92-0-106908-5
    .
  6. ^ "Production and Supply of Molybdenum-99" (PDF). IAEA. 2010. Archived (PDF) from the original on 2022-10-09. Retrieved 4 March 2018.
  7. ^ Greenblatt, Jack A. (2009). "Stable and Radioactive Isotopes: Industry & Trade Summary" (PDF). Office of Industries. United States International Trade Commission. Archived (PDF) from the original on 2022-10-09.
  8. doi:10.1016/j.apradiso.2005.03.004. Archived
    (PDF) from the original on 2022-10-09.
  9. ^ Branch, Doug (2012). "Radioactive Isotopes in Process Measurement" (PDF). VEGA Controls. Archived (PDF) from the original on 2022-10-09. Retrieved 4 March 2018.

External links

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